Yes, it is done before but it depends on your present crank now. If you see 5 lock nuts on the crank holding the chain ring, then you can just buy the smaller 39T (130BCD) chainring and bolt onto the present set up BUT if your present chain ring is the one piece type (means the chain ring cannot be taken out), then you have to buy another crank which cost quite substantial. The cheapest I notice is about RM180 for double chainring. Then the FD adapter and the FD itself and finally the shifter which are sold in pairs.  All in all averaging about RM600.

On the other hand if you mod the rear first, you need an RD, shifter (also a pair), a cassette and new chain and cable. Let me do the calculation again,  Gear inches is our aim. Simplified means, the bigger the number, the lower the gear and also the easier it is to pedal, in the expense of speed of course. You cannot have both.   so, if your setup is 7 speed, usually the rear cogs are 13T to 28T . The front , I assume is 52T because my former Dahon Eco C7 was that size. For this setup, the gear inches ranges from 80.00 GI to 37.14 GI.

OK, let's say you maintain the rear setup and modify a second chain ring. So it's 52/39T with 13/28T at the rear. For this the GI is ,  80.00 GI to 27.85 GI, so that is a gain of 9.19 GI on the lower gear spectrum but no change on the higher gear.

OK, now let's say you go for the 10 speed rear modifications. The rear cassette ranges from 11T (which gives you more speed, you can even pedal when you are going downhill) to 34T. With this the GI will range from
94.54 GI to  30.58 GI. With this you gain 6.56 GI on the lower gear BUT you gain 14.54 GI on the higher gear. Means you can ride faster on flats and downhill. Also sometimes with more gers the ratio gaps are smaller making gear changes fluid. Like with less gears, eg. your pedaling becomes hard so you shift to lower gear but one notch higher the pedaling becomes to free. That's why roadbike gears are near!

In the end, if you have modded the rear and now also modded the front as well, the range is from 94.54 GI to 22.94 GI.    Just for comparison purposes, my Dahon Speed is 3 x 9 speeder. The gear ranges from 96.36 GI to 18.75 GI. That's a very wide range because the chain ring is 53T/40T/30T  and the rear 11T/32T . See picture, pardon, tak cuci bike after last week's ride. 

just bought GTA folding bike 8x2 shimano groupset...
hope the bike will be okay....

RM1100.00 @ yong advance cycle @ ampang putra

yeah expensive, i search for kryptonite as read people recommend it. but if use flimsy padlock still no use right he he. I read somewhere that we should invest in locks that is 25% the price of the bike...ha ha ha

anyway, still have doubt leaving the bike in lrt station as Azam highlighted earlier on how easy to open up folding bike with simple tools and I agree too. And still also haven't bring the folding bike in lrt to go to work as it's seems mafan. so end up I still can't use the bike as my original intention - to commute train+bike to office, lol. my dad is laughing at me and tell me why I bother about it as he still can send me to lrt...arghhh!

right now it has become just an exercise tool, which is also fine though.

Eh who said female have to wear skirt and high heels ?

that's what I plan to do. My office has shower.

expand ur knowledge bro.... 

http://www.baikbike.com/follow-guans-lead/

http://chanjerping.com/

http://www.thestar.com.my/Lifestyle/Featur...-a-green-route/

yeah, lucky me. but last time I once work in office with no shower. Sometimes I go jogging and other activities after work and wait for my dad pick me up later at night, I can also bath in the office toilet    so I guess that's fine too. but I think I was just lucky as that office is like a close-knit- family- type of people in the office and the toilet is in the office itself. so it's just like a home, no one bothered when I take bath there.

this is the reply frm unker budgee... 
https://forum.lowyat.net/index.php?showtopi...post&p=69402575

Hey guys, so today my first day ride my bike to office + komuter. I decided to ditch Putra LRT (KJ Line) as it is not feasible at all given the human volume that ride lrt during office hour. I have tried bring bike once during non office hour (10 am) in KJ Line LRT from Gombak to Dang Wangi station, no bag, passed.

For today, cycle to Komuter Sentul from Gombak, in about 30 minutes. I was late from home about 7:45 am so traffic is there. Really ride defensively as office people are fierce when they drive to office,  , cars don't care if you are there really at the edge of the road and still squeeze you. I thought motorbikes are my allies but they are no less competitive in the race of who gonna reach office first    A motorbike still squeeze in between me and a car and give me the 'look'. LOL, these people love office too much  So, what I'm saying is we really really ride defensively in morning traffic.

Nevertheless, made it safely to Komuter Sentul in 30 minutes, which is 10 minutes earlier than the first time I ride it in trial ride in the evening. In komuter station, I fold it trolley style with the handle not folded so I can push it around like trolley. I look at the guard if he gonna stop me, I bring my bike bag too, just in case. I asked the guard, can I go in like this, and he give me an ok nod, so I push my bike like trolley in to the lift and to platforms. Arrived the other station also, I push it like trolley into the lift. This reminds me sometimes the lifts in komuter will not work, so I make a mental note that when those times happen it will be a bit trouble to carry it up and down the stairs. Then I continue my cycle to my office about 5 minutes.

My office is at level 3 with no lift, so I fold it and bring it up the stairs. The guards said I can leave it under the stairs, but I said i don't have lock so scared it will be gone. They said it's ok, there is CCTV, but I don't wanna take chances hehehe 

and regarding shower, for today I don't feel it's necessary as I sweat only like when I walk to office. I do bring toiletries just in case I needed one.

Anyway, so I arrived safely in about 50 minutes including komuter waiting time. Gombak to Jalan Tun Ismail. I think for now I'll do this when I don't have to go elsewhere after office. Overall, it's nice to cycle to office than standing in lrt for one hour to arrive my office, only to continue another 10 minutes walk. Cycling is definitely better.

Here are pictures how I fold it like trolley in komuter. And in office the bike fits behind my chair at my desk.